Buying offsets is not shifting the blame, it's paying someone else to fix the problem. The reason for that should be that you either have no cost effective way

Buying offsets is not shifting the blame, it's paying someone else to fix the problem. The reason for that should be that you either have no cost effective way to offset the carbon yourself, or there is a very attractive market for the offsets. If demand were x+100, and theoretically some company wouldn't be able to afford to buy the offsets, it wouldn't somehow have ended up with the blame of Shell, they would just have found no one to solve their problem for them and would have to fix it themselves. Of course this is assuming that whoever is selling the offsets is actually performing the task of carbon offsetting effectively, something that many believe is not actually happening so that puts things into even more murky waters.